Welcome to ReefCentral.
Because of the sheer size of our forum, we've been forced to limit selling and trading to members who've met a couple of criteria. (If you're seeing this message, you haven't met them yet.) Please take a moment to acquaint yourself with our selling/trading rules to help make your stay a long and rewarding one.
Selling and trading on ReefCentral.

In the product review there is a paragraph that I don't quite understand and maybe you would clarify for me please...

The first step in getting the reactor working is regulating its water feed. Large tanks need a higher flow through a given reactor than small tanks. Determining the actual flow through the system requires a little effort and time to figure out, as described below. The best way to do this is to start with a flow of 1-2 liters per hour through the system. Fortunately for me, I needed a large flow so I left the control valves fully open. The effluent end of the pipework was arranged so that it entered my sump in an area of high water flow/turbulence. This helped blow off any excess CO2 in the effluent and mix the high alkalinity and calcium contents of the effluent.

Referring to regulating the reactor water feed. Are you referring to regulating the effluent flow by use of the Flow Regulator Tap? I am running a GEO 612 on a 150G Reef Tank and it uses an Eheim pump but I am thinking of replaing the Eheim with a Pan World Pump.

My 612 reactor is fed by a MJ1200 as well. What should the flow rate inside the reactor chamber be? The 818 is powered by a Pan World pump but the 612 is powered by an Eheim 1048 pump. I am wondering if there would be a benefit to swapping out my pump for a Pan World. Can you tell me the flow rating on the Pan World pump on your 818?